Current experience with antiviral therapy for acute herpes zoster

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia (PHN) is a common, serious, painful complication of herpes zoster. Corticosteroids have anti-inflammatory properties, and might be beneficial. This is an update of a review first published in 2008, and previously updated in 2013.

OBJECTIVES

To assess the effects (benefits and harms) of corticosteroids in preventing postherpetic neuralgia.

SEARCH METHODS

We updated the searches for randomised controlled trials (RCTs) of corticosteroids for preventing postherpetic neuralgia in the Cochrane Neuromuscular Specialised Register, CENTRAL, MEDLINE, Embase, two other databases, and two trials registers (June 2022). We also reviewed the bibliographies of identified trials, contacted authors, and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all RCTs involving corticosteroids given by oral, intramuscular, or intravenous routes for people of all ages, with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo, but not with other treatments.

DATA COLLECTION AND ANALYSIS

Two review authors independently identified potential articles, extracted data, assessed the risk of bias of each trial, and the certainty of the evidence. Disagreement was resolved by discussion among the co-authors. We followed standard Cochrane methodology.

MAIN RESULTS

We identified five trials with a total of 787 participants that met our inclusion criteria. No new studies were identified for this update. All were randomised, double-blind, placebo-controlled parallel-group studies. The evidence is very uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection in preventing postherpetic neuralgia six months after the onset of herpes (risk ratio (RR) 0.95, 95% confidence interval (CI) 0.45 to 1.99; 2 trials, 114 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)). The three other trials that fulfilled our inclusion criteria were not included in the meta-analysis because they did not provide separate information on the number of participants with PHN at six months. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no observed differences in serious (RR 1.65, 95% CI 0.51 to 5.29; 5 trials, 755 participants; very low-certainty evidence (downgraded for serious risk of bias and very serious imprecision)), or non-serious adverse events (RR 1.30, 95% CI 0.90 to 1.87; 5 trials, 755 participants; low-certainty evidence (downgraded for serious risk of bias and serious imprecision)) between the corticosteroid and placebo groups. One of these trials was at high risk of bias because of incomplete outcome data, two were at unclear risk of bias, and the other was at low risk of bias. The review was first published in 2008; no new RCTs were identified for inclusion in subsequent updates in 2010, 2013, and 2023.

AUTHORS' CONCLUSIONS

Based on the current available evidence, we are uncertain about the effects of corticosteroids given orally during an acute herpes zoster infection on preventing postherpetic neuralgia. Corticosteroids given orally or intramuscularly may result in little to no difference in the risk of adverse events in people with acute herpes zoster. Some researchers have recommended using corticosteroids to relieve the zoster-associated pain in the acute phase of the disease. If further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life, as well as updated measures of pain.

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia is a common, serious painful complication of herpes zoster. Corticosteroids are anti-inflammatory and might be beneficial. This is an update of a review first published in 2008 and previously updated in 2010.

OBJECTIVES

To examine the efficacy of corticosteroids in preventing postherpetic neuralgia.

SEARCH METHODS

We updated the searches for randomised controlled trials (RCTs) of corticosteroids for preventing postherpetic neuralgia in the Cochrane Neuromuscular Disease Group Specialized Register (16 April 2012), CENTRAL (2012, Issue 3), MEDLINE (January 1966 to April 2012), EMBASE (January 1980 to April 2012), LILACS (January 1982 to April 2012), and the Chinese Biomedical Retrieval System (1978 to 2012). We also reviewed the bibliographies of identified trials, contacted authors and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all RCTs involving corticosteroids given by oral, intramuscular, or intravenous routes for people of all ages with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo but not with other treatments. We did not include quasi-RCTs (trials in which a systematic method of randomisation such as alternation or hospital number was used).

DATA COLLECTION AND ANALYSIS

Two authors identified potential articles, extracted data, and independently assessed the risk of bias of each trial. Disagreement was resolved by discussion among the co-authors.

MAIN RESULTS

Five trials were included with 787 participants in total. All were randomised, double-blind, placebo-controlled parallel-group studies. We conducted a meta-analysis of two trials (114 participants) and the results gave moderate quality evidence that oral corticosteroids did not prevent postherpetic neuralgia six months after the onset of herpes (RR 0.95, 95% CI 0.45 to 1.99). One of these trials was at high risk of bias because of incomplete outcome data, the other was at low risk of bias overall. The three other trials that fulfilled our inclusion criteria were not included in the meta-analysis because the outcomes were reported at less than one month or not in sufficient detail to add to the meta-analysis. These three trials were generally at low risk of bias. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no significant differences in serious or non-serious adverse events between the corticosteroid and placebo groups. There was also no significant difference between the treatment groups and placebo groups in other secondary outcome analyses and subgroup analyses. The review was first published in 2008 and no new RCTs were identified for inclusion in subsequent updates in 2010 and 2012.

AUTHORS' CONCLUSIONS

There is moderate quality evidence that corticosteroids given acutely during zoster infection are ineffective in preventing postherpetic neuralgia. In people with acute herpes zoster the risks of administration of corticosteroids do not appear to be greater than with placebo, based on moderate quality evidence. Corticosteroids have been recommended to relieve the zoster-associated pain in the acute phase of disease. If further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life.

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia is a common serious complication of herpes zoster. Corticosteroids are anti-inflammatory and might be beneficial.

OBJECTIVES

To examine the efficacy of corticosteroids in preventing postherpetic neuralgia.

SEARCH STRATEGY

We updated the searches for randomised controlled trials of corticosteroids for preventing postherpetic neuralgia in MEDLINE (January 1950 to February 2010), EMBASE (January 1980 to February 2010), LILACS (January 1982 to February 2010), the Chinese Biomedical Retrieval System (1978 to 2010 ) and the Cochrane Register of Controlled Trials (CENTRAL) (The Cochrane Library Issue 1, 2010). We also reviewed the bibliographies of identified trials, contacted authors and approached pharmaceutical companies to identify additional published or unpublished data.

SELECTION CRITERIA

We included all randomised controlled trials involving corticosteroids given by oral, intramuscular or intravenous routes for people of all ages with herpes zoster of all degrees of severity within seven days after onset, compared with no treatment or placebo, but not with other treatments.

DATA COLLECTION AND ANALYSIS

Two authors identified potential articles, extracted data and assessed quality of each trial independently. Disagreement was resolved by discussion with other co-authors.

MAIN RESULTS

Five trials were included with 787 participants in total. All were randomised, double-blind, placebo-controlled parallel group studies. No new trials were identified in the 2010 update. In the updated version we conducted a meta-analysis of two trials, and the results showed that oral corticosteroids did not prevent postherpetic neuralgia six months after the herpes onset (RR, 0.95; 95% CI 0.45 to 1.99). The three other included trials also had similar results although their data could not be included in the meta-analysis. Adverse events during or within two weeks after stopping treatment were reported in all five included trials. There were no significant differences in serious or non-serious adverse events between the corticosteroids and placebo groups.

AUTHORS' CONCLUSIONS

Corticosteroids given acutely during zoster infection are ineffective in preventing postherpetic neuralgia. In people with acute herpes zoster the risks of administration do not appear to be great. Corticosteroids have been recommended to relieve the zoster-associated pain in the acute phase of disease; if further research is designed to evaluate the efficacy of corticosteroids for herpes zoster, long-term follow-up should be included to observe their effect on the transition from acute pain to postherpetic neuralgia. Future trials should include measurements of function and quality of life.

Corticosteroids for preventing postherpetic neuralgia

BACKGROUND

Postherpetic neuralgia is a common serious complication of herpes zoster. Corticosteroids are anti-inflammatory and might be beneficial.

OBJECTIVES

To examine the efficacy of corticosteroids in preventing postherpetic neuralgia.

SEARCH STRATEGY

Search for randomised or quasi-randomised controlled trials for corticosteroids for preventing postherpetic neuralgia in MEDLINE (1950 to 2006), EMBASE (1980 to 2006), LILACS (1982 to 2005), the Chinese Biomedical Retrieval System (1978 to 2006) and the Cochrane Register of Controlled Trials (CENTRAL) (Cochrane Library Issue 3, 2006). Date of most recent search: September 2006.

SELECTION CRITERIA

Types of studies: quasi-randomised or randomised controlled trials.

TYPES OF PARTICIPANTS

people of all ages with herpes zoster of all degrees of severity within seven days after onset. Types of interventions: all kinds of corticosteroids given by oral, intramuscular or intravenous routes during the acute stage (starting within one week of onset of the rash) compared with no treatment or placebo, but not with other treatments. We also included trials which compared corticosteroids plus routine treatment with placebo plus routine treatment. Types of outcome measures: Primary: the presence of postherpetic neuralgia six months after the onset of the acute herpetic rash. Secondary: pain severity measured by a validated visual analogue scale or numerical descriptive scale after three, six and 12 months; quality of life measured with the short form 36 questionnaire after six months; adverse events during or within two weeks after stopping treatment.

DATA COLLECTION AND ANALYSIS

Data were extracted by two independent reviewers.

MAIN RESULTS

Five trials were included with altogether 787 participants. All were randomised, double-blind, placebo-controlled parallel group studies. Our primary outcome measure was the presence of postherpetic neuralgia six months after the onset of the acute herpetic rash. There was no significant difference between the corticosteroid and control groups for the primary outcome (RR 1.27, 95% CI 0.20 to 7.97). There was also no significant difference between the corticosteroid plus antiviral agents and placebo plus antiviral agents groups for the primary outcome (RR 0.90, 95% CI 0.40 to 2.03). No included trials evaluated pain severity with a validated visual analogue scale or numerical descriptive scale and also no trials measured quality of life with the Short Form 36 questionnaire. Adverse events during or within two weeks after stopping treatment were reported by all five included trials, but after meta-analysis, there was no significant difference in any serious adverse event (death, acute cardiac insufficiency, rash dissemination, bacterial pneumonia or haematemesis) or non serious adverse event (dizziness, nausea, vomiting, hypertension or hyperglycaemia).

AUTHORS' CONCLUSIONS

There was insufficient evidence to conclude that corticosteroids are safe or effective in the prevention of postherpetic neuralgia. More randomised controlled trials with a greater number of participants are needed to determine reliably whether there is real benefit (or harm) from the use of corticosteroid therapy to prevent postherpetic neuralgia. Future trials should measure function and quality of life.

Herpes zoster of the head and limbs: electroneuromyographic and clinical findings in 158 consecutive cases

OBJECTIVES

To quantify electromyographic and neurographic changes and to correlate them with the clinical data of outpatients with herpes zoster.

DESIGN

Prospective case series.

SETTING

Outpatient department.

PATIENTS

A consecutive, unselected series of 158 outpatient cases (88 women, 70 men; mean age, 64y) of herpes zoster of the head and limbs.

INTERVENTIONS

Not applicable.

MAIN OUTCOME MEASURES

Blink reflex and electromyography and motor and sensory nerve conduction velocities of nerves and muscles corresponding to affected dermatomes.

RESULTS

Postherpetic neuralgia (PHN), segmental zoster paresis, and polyneuropathy were found in 31%, 19%, and 2.5% of cases, respectively. Absence or reduction of sensory action potential amplitudes, blink reflex areas, and compound muscle action potential amplitudes were found in 60%, 31%, and 18% of cases, respectively. Sensory and motor conduction velocities and motor and blink reflex latencies were nearly always normal or only slightly slowed. Electromyographic signs of abnormal spontaneous activity were found in 36% of the cases. Electrophysiologic alterations were correlated among themselves, with age, with presence of segmental zoster paresis, and with absence of antiviral therapy. The extent of the skin rash (number of dermatomes affected by herpes zoster) was the only variable predictive of disappearance or improvement of PHN.

CONCLUSIONS

Sensory axonal neuropathy, often associated with similar motor involvement, can be shown by classical electrophysiologic methods in herpes zoster. The severity of damage to motor fibers was related to damage to sensory fibers, but no relation was found between peripheral axon damage and PHN. The site of motor system damage may be the ventral roots, plexus, or peripheral nerve. The probability of complications and the severity of sensory and motor peripheral axonal damage were increased in older patients. Appropriate antiviral therapy seems to reduce the incidence of segmental zoster paresis and the severity of damage to the peripheral fibers. A reduced extent of herpetic rash was the only factor to correlate with a good outcome of PHN.

Acute Herpes zoster in Tayside: demographic and treatment details in immunocompetent patients 1989-1992

Medical records of 105 patients admitted to Tayside hospitals with acute Herpes zoster without underlying immunosuppression were examined retrospectively for the period 1984-1992. In this elderly population (median age: 79 years) there was a female preponderance (70.5%), most admissions were for trigeminal zoster (49.5%) and length of stay ranged from 1-70 days (median: 11 days), indicating significant morbidity. There was a wide variation in both pre-admission and inpatient treatment; 53.3% of patients did not receive any anti-viral therapy prior to admission, and prescribing patterns for in-patients revealed marked differences, according to the dermatome affected. Idoxuridine 5% solution was prescribed by 15.24% of General Practitioners. Given the significant morbidity and associated costs of Herpes zoster, and that existing anti-viral agents exert maximal benefit when administered early in the course of the disease, recommendations are made with respect to appropriate therapy, and auditing current management of this serious illness, which is expected to increase in prevalence as the population ages.

Electrophysiological findings in peripheral fibres of subjects with and without post-herpetic neuralgia

The peripheral nervous system was studied using classical electrophysiological methods in 23 subjects with post-herpetic neuralgia (PHN), and compared with the same parameters in 64 herpes zoster (HZ) patients without PHN. The findings indicated sensory axonopathy, the severity of which varied in different patients. Ten percent of all cases showed segmental paresis corresponding to dermatomes affected by HZ. In another 17% of patients axonal motor damage was only detectable by EMG as denervation. No statistically significant difference was found between the two groups in the mean percentage differences of the electrophysiological data for peripheral sensory fibres with respect to mean control values, or between sides affected by HZ and healthy sides. Hence HZ is associated with sensory axonopathy, the severity of which is similar, on the whole, in the groups with and without PHN and stable in time. This suggests that damage to peripheral large-diameter sensory fibres is not the cause of PHN.

Acyclic nucleosides as antiviral compounds

Acyclovir is an effective drug for the treatment of HSV and VZV infections, which after phosphorylation to the triphosphate, inhibits viral DNA polymerase. Acyclovir has low oral bioavailability, therefore prodrugs have been developed, and the L-valyl ester, valaciclovir, recently has been licensed for the treatment of shingles. Ganciclovir is used against CMV, and famciclovir, a lipophilic prodrug of penciclovir, is marketed for shingles. The acyclic nucleoside phosphonates are active against thymidine kinase-resistant viral strains. Promising analogs are PMEA (in clinical trial for the treatment of AIDS) and (S)-HPMPC (good in vivo activity against HSV, VZV, CMV, and EBV). Oligonucleotides incorporating acyclic nucleosides at the 3'-and 5'-ends, or constituted of amino acyclic nucleosides, are resistant to cleavage by nucleases and may be useful in antisense and/or antigene therapy. HEPT is active against HIV-1: It binds in a hydrophic pocket on reverse transcriptase, rather than in the polymerase active site. Some acyclic nucleosides are potent inhibitors of purine and pyrimidine nucleoside phosphorylase. These compounds may have a therapeutic niche in combination therapy with antiviral and anticancer nucleosides, and in the treatment of diseases involving the T-cell.

Antiviral therapy of acute herpes zoster in older patients

Although herpes zoster (shingles) can occur in anyone with a history of chickenpox, it is more prevalent and usually more severe in older patients (i.e. persons over 50 years of age). While the cutaneous manifestations of shingles usually resolve in approximately 4 weeks, the pain can persist for several months, or even years in the untreated patient. This pain following healing of the skin, termed post-herpetic neuralgia (PHN), can be very severe. Three well tolerated and effective antiviral drugs are available for the therapy of acute herpes zoster. The nucleoside analogues, aciclovir, famciclovir and valaciclovir, appear to shorten the duration of PHN to a similar degree, but none affects the incidence of PHN. Aciclovir is taken 5 times daily for 7 days, while famciclovir is taken 3 times daily for 7 days. Valaciclovir, the L-valyl ester of aciclovir, when taken orally, produces plasma levels of aciclovir equivalent to those seen following intravenous administration of aciclovir. Valaciclovir has not only been proved to be more efficient than aciclovir (i.e. 3 times daily administration) but also more effective than aciclovir in shortening the duration of PHN. Current studies are determining the relative efficacy of valaciclovir versus famciclovir. Presently, a fourth drug, sorivudine, is being compared with aciclovir for the therapy of acute herpes zoster in older patients, but data from these trials are not yet available. Corticosteroids have been used to treat herpes zoster for much longer than the antiviral drugs, but the effect of corticosteroids on PHN does not appear to be consistent. Corticosteroids plus aciclovir did not provide an added benefit over aciclovir alone in one study but this combination did appear to improve the quality of life of older patients in another investigation. The recent availability of the varicella zoster vaccine may cause shingles to be an uncommon and/or mild disease by the mid twenty-first century. Meanwhile, the search continues for more effective and efficient therapies for acute herpes zoster with the primary goal in older patients to affect the most important sequela of zoster in this population, PHN.